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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ce963e16871899044920461afd0947ce1dbad23b2f1aa047adbf5b0d1a23ba' 
  AND token = 'mcz9+7pbhEc1dILfu8SB8PWo1zHLNGXMPLIYlJL622M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}